The French mathematician, physicist, and religious thinker whose Pensées offered the most powerful early modern defense of Christianity through analysis of human contradiction, and whose wager argument remains one of the most discussed in the philosophy of religion.
pascal
French mathematician, physicist, and Jansenist Catholic apologist (1623–1662) whose Pensées presented Christianity as the only adequate account of human contradiction, whose wager argument introduced decision theory to natural theology, and whose Provincial Letters established modern French prose.
Life
Blaise Pascal was born on 19 June 1623 in Clermont-Ferrand, in Auvergne. His mother died when he was three; his father Étienne, a magistrate and accomplished amateur mathematician, took charge of his education and that of his sisters Gilberte and Jacqueline. The family moved to Paris in 1631 so that Étienne could supervise Blaise's instruction directly, on the unusual principle (defended in his sister Gilberte Périer's biography of her brother) that he should learn no mathematics before fifteen.
The principle did not survive contact with the boy. At twelve, Pascal worked out independently — with charcoal on flagstones — that the angles of a triangle sum to two right angles, and was given access to Euclid. He attended the meetings of Marin Mersenne's circle as a teenager, alongside Descartes, Roberval, Desargues, and Fermat. At sixteen he wrote a treatise on conic sections that contained what is now called Pascal's theorem; Descartes, on receiving it, refused to believe it had been composed by a boy of sixteen.
The practical and scientific work followed. To assist his father, then engaged in tax assessment in Rouen, Pascal designed a mechanical calculator — the pascaline — between 1642 and 1645, one of the first digital computing devices. Around 1646, prompted by Torricelli's barometric experiment, he conducted the experiments demonstrating atmospheric pressure and the existence of the vacuum, most famously the Puy-de-Dôme experiment carried out by his brother-in-law Florin Périer on 19 September 1648 — carrying a mercury barometer up a mountain and observing the column's fall as altitude increased. This was a decisive experimental refutation of the Aristotelian horror vacui.
The correspondence with Fermat in 1654 on the problem of points — how to divide stakes in an interrupted game of chance — founded modern probability theory. Pascal's Traité du Triangle Arithmétique (composed 1654, published 1665) developed the arithmetic triangle that bears his name and proved by induction.
On 23 November 1654, between approximately 10:30 PM and 12:30 AM, Pascal experienced the religious episode he recorded on a paper subsequently called the Mémorial, sewn into the lining of his coat and discovered after his death:
Fire.
God of Abraham, God of Isaac, God of Jacob, not of the philosophers and scholars.
Certainty, certainty, feeling, joy, peace.
He withdrew from worldly mathematical work and from the Parisian salons, retired to the Jansenist community at Port-Royal, and devoted his remaining seven years to religious writing. He died on 19 August 1662, aged 39, of complications from a long-standing illness now generally identified as a combination of severe digestive disorder and possibly tuberculous meningitis.
The Lettres Provinciales
The immediate occasion of Pascal's first religious work was the controversy between the Jansenists — centered at the convent of Port-Royal, deriving from the Augustinian theology of Cornelis Jansen (1585–1638), Bishop of Ypres — and the Jesuits, who pressed for the condemnation of five propositions extracted from Jansen's Augustinus (1640). Antoine Arnauld, the principal Jansenist theologian, faced expulsion from the Sorbonne in early 1656. Pascal, recruited by Arnauld and others, composed eighteen pseudonymous Lettres écrites à un provincial between January 1656 and March 1657.
The early letters defended Arnauld's theological position. The middle letters mounted a devastating polemical attack on Jesuit casuistry, citing the manuals of Antonio Escobar y Mendoza, Étienne Bauny, and others to argue that the Jesuits had so attenuated moral demands through the doctrines of probabilism, mental reservation, directing the intention, and the like as to have made sin practically unattainable for the well-counseled penitent. The later letters returned to theological substance, defending efficacious grace against the Jesuit alternative of sufficient grace.
The Provincial Letters were a literary sensation. Voltaire later called them the first work of French prose — the foundational text of modern French style, displacing the convoluted manners of earlier prose with sharp, polished, polemically lethal sentences. Sainte-Beuve's monumental Port-Royal (5 vols., 1840–59) remains the principal historical treatment of the controversy.
The Pensées
Pascal's Apology for the Christian Religion, the major theological project of his last years, was never completed. At his death he left several hundred fragments — on individual scraps of paper, some bundled and labeled in folders he had begun to organize. Port-Royal published a selection in 1670 under the title Pensées de M. Pascal sur la religion et sur quelques autres sujets, smoothing and rearranging the fragments to create a more orthodox presentation.
The modern critical history of the text is the history of recovering the original order. Léon Brunschvicg's 1897 edition reorganized by topic; Louis Lafuma in 1951 reproduced the order of the Copies — two seventeenth-century manuscript copies preserving an arrangement closer to Pascal's own — demonstrating that Pascal had begun to organize roughly two-thirds of the material into twenty-eight folders by topic. Philippe Sellier's 1976 edition (revised 1991) is the current scholarly standard. Anthony Levi's translation (Penguin Classics, 1995) and the Krailsheimer translation are the standard English versions.
The argument of the Pensées, insofar as the fragments allow reconstruction, proceeds in two stages. The first stage establishes the misery of man without God: the wretchedness and grandeur of the human condition, the impossibility of resting in the world, the futility of philosophical attempts to ground human life in nature or reason, the boredom that drives men to perpetual divertissement. The second stage establishes the answer in God through Christ: only the Christian doctrine of the Fall accounts for the contradiction of human grandeur and misery, and only Christ supplies the mediator the contradiction demands. Pascal proposed to argue, against the Cartesian and rationalist theologians, that the deus absconditus (hidden God) of the prophets is the actual God, and that the philosophers' God of demonstration is at best an empty abstraction.
Key themes: the disproportion of man and the two infinites (fragment 199 Sellier); the three orders of body, mind, and charity, each infinitely transcending the lower (308 S); the human heart and its reasons — "Le cœur a ses raisons que la raison ne connaît point" (423 S); the wretchedness and grandeur of man (114, 116 S); divertissement and the inability to sit alone in a room (132 S); the hidden God (242 S); and the famous Wager.
The Wager
Fragment 418 (Sellier), the Infini-Rien, presents Pascal's decision-theoretic argument for religious commitment. The argument: human reason cannot demonstrate whether God exists. We must therefore wager. If we wager that God exists and live accordingly, we lose finite goods if wrong but gain infinite goods (eternal blessedness) if right; if we wager against and live accordingly, we gain finite goods if right but lose infinite if wrong. Multiplying probability and payoff, the rational choice is to wager on God's existence, since any positive probability multiplied by an infinite payoff exceeds any finite alternative.
The argument is widely regarded as the first formal use of expected utility reasoning, predating its codification by Daniel Bernoulli (1738) by eighty years. Ian Hacking's The Emergence of Probability (Cambridge University Press, 1975) traces the Wager's significance for the history of probability theory; Jeff Jordan's Pascal's Wager (Oxford University Press, 2006) surveys modern philosophical responses, including the many-gods objection and the question whether infinite utilities make coherent sense in decision theory.
Pascal's own framing is less concerned with proof of existence than with the practical reorientation of life: the wager is addressed to the libertine who acknowledges he cannot decide on rational grounds, and shows him that practical reason already does decide. The instruction that follows the wager — take holy water, attend masses, follow the practices that have brought belief to others — makes clear that belief follows action, not the reverse.
Significance
Pascal's importance crosses the modern division of disciplines. As a mathematician, his work in projective geometry, probability, and the arithmetic triangle was foundational; the SI unit of pressure bears his name in recognition of his experiments. As a religious thinker, the Pensées shaped a tradition of Christian reflection running through Kierkegaard (who repeatedly cited him), Newman, Dostoevsky, Berdyaev, Simone Weil, and twentieth-century existentialist Catholicism. The diagnosis of human contradiction — grandeur and misery, the impossibility of rest, the perpetual flight from self through divertissement — was absorbed into the existentialist tradition broadly construed. The wager has remained a perennial topic in the philosophy of religion.
As a prose stylist, Pascal joined Montaigne and Descartes as one of the three foundational French prose writers of the seventeenth century. The aphoristic compression of the fragments — "Le silence éternel de ces espaces infinis m'effraie" (201 S) — belongs in any anthology of French literature.